It is known that the breath odour can provide an indication of certain conditions. A straightforward example is that of halitosis, or xe2x80x9cbad breathxe2x80x9d. Another example is ketosis, wherein the presence of sweet smelling ketones and aldehydes in the breath can be an indication of diabetes.
The present invention provides a method and apparatus for detection numerous conditions from the gaseous or volatile species present in breath. For the avoidance of doubt, the terms xe2x80x9cgas xe2x80x9dand xe2x80x9cgases xe2x80x9dare taken to comprise any species present in the gas phase, including vapours from volatile liquids.
According to a first aspect of the invention there is provided a method for detecting the occurrence of a condition in a respiring subject comprising the steps of:
introducing emitted subject repiratory gases to a gas sensing device;
detecting certain species present in said emitted subject respiratory gases with said gas sensing device; and
correlating the presence of said species with the occurrence of the condition.
The method is rapid, since the analysis is directxe2x80x94there is no need to perform time consuming culturing steps. Furthermore, the method provides non-invasive clinical screening and monitoring of many conditions.
The respiring subject may be human.
The gas sensing device may comprise an array of semiconducting organic polymer gas sensors.
The gas sensing device may comprise a gas sensitive material, of which an electrical property may vary on exposure to gases. The gas sensitive material may comprise semiconducting organic polymer.
The gas sensing device may comprise a mass spectrometer or a GC-MS device.
The emitted respiratory gases may be obtained from a ventilator. In this way, on-line monitoring for the occurrence of a condition, or monitoring of the progress of a condition, is possible.
The emitted subject respiratory gases may be introduced directly to the gas sensing device.
The occurrence of an infection or a disease state may be detected.
The occurrence of a lung disorder may be detected, which may be pneumonia, tuberculosis or a yeast infection.
The occurrence of a gastrointestinal infection may be detected.
The occurrence of diabetes may be detected.
The presence of alcohol may be detected.
The occurrence of phenylketonuria may be detected.
According to a second aspect of the invention there is provided a detector for detecting the occurrence of a condition in a respiring subject comprising a gas sensing device and means for introducing emitted subject respiratory gases to the gas sensing device, which device is adpated to recognise the occurrence of a condition in the subject when certain species present in said emitted respiratory gases are detected.
The means for introducing emitted respiratory gases to the gas sensing device may comprise a ventilator. The gas sensing device may be directly connected to the ventilator.